1. Field of the Invention
This invention relates to a processing method of plural workpieces using plural combined processing machines, wherein each combined processing machine selectively uses plural processing tools in order to variously process the workpieces, and wherein the combined processing machines process the workpieces efficiently.
2. Discussion of the Background
Among conventional machine tools, there are selected and used a turning machine, a drilling machine, a boring machine, a milling machine, a planing machine, a broaching machine, a grinding machine, etc. which are selected according to appropriateness for the process to be applied to a workpiece. Further, there is a combined processing machine which is numerically controlled (NC) in order to variously process the workpiece. For example, Japanese examined patent application publication JP-07-061585-B discloses one combined processing machine which lathes and grinds the workpiece. This prior art has plural turrets with plural tools and changes the turrets from/to a tool spindle head in order to process (e.g., lathe, mill, drill, grind and etc.) the workpiece with controlling the X, Y and Z axes.
A conventional flexible manufacturing system (FMS) has plural NC machine tools, an automatic workpiece transfer device which loads/unloads the workpiece into/from the machine tools, and a controller which controls the machine tools in the system in accordance with the process program corresponding to each workpiece. Japanese laid-open patent application publication JP-2000-280149-A discloses a processing method of the FMS. This prior art creates a heat treatment schedule according to an input order data and creates a pre-treatment schedule according to the heat treatment schedule. Therefore, the workpiece is processed by the pre-treatment equipment according to the pre-treatment schedule and is processed by the heat treatment equipment according to the heat treatment schedule.
Japanese laid-open patent application publication JP-07-148636-A discloses a flexible transfer line (FTL) which arranges plural machining centers and accounts for a fluctuation of a volume of processing the workpieces.
Most studies, however, have not focused on arranging plural machines for efficient processing (e.g., the combined processing machine of JP-07-061585-B, NC turning center, machining center, etc.) in order to process the workpiece form the beginning to the end according to the processing method (e.g. JP-2000-280149-A). Especially, the conventional FTL arranges plural machining centers which only perform cutting processes. Further, the conventional FTL is for a block-like workpiece (e.g. an engine cylinder block) fixed on a table to be cut.